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Scan for outdated or missing drivers - takes under a minuteDriver Scan →Clear out junk files and repair common Windows errorsFree Scan →If Categorize is missing, disabled, or shows the wrong list in a shared Inbox, the mailbox is usually being opened as a shared folder rather than as a separate account. In New Outlook for Windows, Microsoft supports shared-mailbox categories when the mailbox is added under Your accounts.
Adding the mailbox to Shared with me is not always enough. You may need to promote an automatically mapped mailbox to a full account, or add it manually, and you need the appropriate Exchange permissions.
1. Add the shared mailbox as an account
First check whether the shared mailbox appears under Your accounts. This is the supported configuration for shared-mailbox settings such as Categories, Rules, Notifications, and Automatic Replies.
For an automatically mapped mailbox
- In New Outlook, select the Settings gear.
- Go to Accounts > Shared with me.
- Select the shared mailbox.
- Select Convert. Microsoft may label this action Promote it to a full account if the mailbox was previously added.
After conversion, the mailbox should appear under Your accounts. If it does not, repeat the conversion step or ask your Microsoft 365 administrator to check your mailbox permissions.
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For a mailbox that was not automatically added
- Open Settings > Accounts > Shared with me.
- Select + Add.
- Enter the shared mailbox details and follow the prompts.
Promoting or adding the mailbox requires Full Access permission. Some New Outlook versions may not yet expose the account-adding feature, so the exact controls can vary between installations.
2. Select the shared mailbox before managing categories
Once the mailbox is listed under Your accounts, open its account-specific settings:
- Open Settings.
- Use the account selector, if shown, to choose the shared mailbox.
- Open Categories.
The category list displayed for the shared mailbox is separate from the list for your personal mailbox. If you create or edit a category while your personal account is selected, you will not be changing the shared mailbox’s category settings.
Microsoft’s current New Outlook documentation lists Categories as a supported shared-mailbox setting. Categories are not included in the current list of unsupported shared-mailbox features, which includes items such as shared Contacts, Notes, Tasks, add-ins, and Archive.
3. Apply an existing category to a message
- Select the message in the shared Inbox.
- On the top toolbar, select Categorize.
- Select the category you want to apply.
You can also right-click the message and choose Categorize, then select the category. To remove a category, open the same menu and clear its check mark.
If the category is not shown in the short picker, select All categories at the bottom of the list. This is different from assuming that the category does not exist or that the mailbox cannot use categories.
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4. Create a category for the shared mailbox
New Outlook provides more than one current route for creating a category:
From a message or calendar event
- Right-click a message or calendar event.
- Select Categorize > New category.
- Enter the category name.
- Optionally select the category icon to choose a color.
- Press Enter.
From the category list
- Open the category list.
- Select Category list.
- Select Create category.
- Enter the name and press Enter.
If the creation control is disabled, the problem is likely permissions or mailbox access rather than the category feature itself.
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In delegated and shared-folder arrangements, Outlook stores category metadata in a hidden message in the mailbox’s Calendar folder. Access to the shared Inbox alone does not provide every permission needed for category operations.
Typical symptoms include:
- Categorize is unavailable or does not respond.
- The category picker is empty or shows only your personal categories.
- The New, Rename, or Delete buttons are disabled.
- Outlook displays a permissions error when you try to change categories.
The required access depends on the sharing model used by your organization:
| Operation | Documented permission in older Microsoft 365 or on-premises arrangements |
|---|---|
| Apply or remove an existing category | Editor or higher on the shared folder |
| Create or delete categories | Owner on the mailbox owner’s Calendar folder |
| Rename a category | The mailbox owner must do it; a delegate cannot rename categories |
For Microsoft’s updated Microsoft 365 calendar-sharing model, the administrator must grant Exchange Full Access, and the mailbox owner must grant Outlook Delegate Access. Restart Outlook after permissions are changed.
Refresh Outlook after a permission change
If your administrator has corrected the permissions but the controls remain unavailable, refresh the shared Calendar connection:
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- Open the shared Calendar.
- Choose Send/Receive > Work Offline.
- Select Work Offline again to return Outlook to online mode.
- Restart New Outlook and test the category controls again.
This is a client-refresh workaround documented by Microsoft for delegated category access. It does not grant permissions by itself.
Use Outlook on the web as a diagnostic comparison
Outlook on the web can help establish whether the issue is limited to the New Outlook client.
To add the mailbox below your primary mailbox:
- Right-click Folders.
- Select Add shared folder or mailbox.
- Enter the shared mailbox name or address.
For Exchange on-premises, right-click your primary mailbox name instead, then choose Add shared folder or mailbox.
To open the mailbox in its own session, select your name on the navigation bar, choose Open another mailbox, enter the address, and select Open. Open it in a separate browser window if you need new-message notifications from the shared Inbox.
If categories work on the web but not in New Outlook, make sure the mailbox has been promoted through Settings > Accounts > Shared with me. A January 29, 2026 Microsoft Q&A report described this exact pattern and reported that adding the mailbox through Shared with me restored access. That report is user-provided and should not be treated as a universal Microsoft fix, but it is a useful diagnostic step.
What not to assume
- Categories are not unsupported in shared mailboxes. Microsoft documents them as supported when the mailbox is added as an account.
- Visibility under Shared with me is not the final test. Look for the mailbox under Your accounts.
- Inbox permission alone is not sufficient for every operation. Calendar permissions can control category metadata.
- Do not look for Manage categories as the primary New Outlook path. Use Categorize, New category, Category list, and Create category.
Quick troubleshooting checklist
| Symptom | Best next step |
|---|---|
| The mailbox is only under Shared with me | Convert or promote it to a full account. |
| The mailbox is not listed at all | Use Settings > Accounts > Shared with me > + Add, or ask an administrator to verify Full Access. |
| The mailbox is under Your accounts but Categories is missing | Confirm that the shared mailbox is selected in the account selector and restart New Outlook. |
| Existing categories can be applied, but new ones cannot be created | Ask for the required Calendar permission, potentially Owner access under the older sharing model. |
| Everything is greyed out after permissions changed | Refresh with the Work Offline toggle, then restart Outlook. |
| Web works but New Outlook does not | Promote the mailbox through Shared with me and verify that your New Outlook version supports adding shared mailboxes as accounts. |
FAQ
Are categories supported in New Outlook shared mailboxes?
Yes. Microsoft supports Categories for a shared mailbox when it is added as an account. A mailbox that is only displayed as an automatically mapped shared folder may not expose the required category settings.
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How do I add a shared mailbox as an account in New Outlook?
Go to Settings > Accounts > Shared with me. Select the mailbox and choose Convert or Promote it to a full account. If it is not listed, choose + Add and follow the prompts.
Why can I apply categories but not create or rename them?
Applying an existing category generally requires Editor-level access to the shared folder. Creating or deleting categories can require Owner access to the mailbox owner’s Calendar, while renaming must be performed by the mailbox owner in some sharing configurations.
Will everyone automatically see categories I assign?
Not in every Outlook scenario. Category visibility depends on whether the item is in a personal mailbox, delegated mailbox, or shared mailbox, as well as the mailbox and Calendar permissions in use.
Is Manage categories the correct command in New Outlook?
Use Categorize, New category, Category list, or Create category in New Outlook. Manage categories is associated with separate classic Outlook on the web instructions and is not the main current New Outlook path.
The Bottom Line
For shared-Inbox categories in New Outlook, the key fix is to make the mailbox a full account: Settings > Accounts > Shared with me, then Convert or + Add. Confirm that it appears under Your accounts. If category creation or editing is still disabled, have your administrator check Full Access and Calendar or Delegate permissions, then refresh and restart Outlook.
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